Interchangeable cartridge data storage system for devices performing diverse functions

ABSTRACT

A system for exchanging digital data among a plurality of hand-held computer devices. Digital signals are written by a first hand-held device to a mini-cartridge that mini-cartridge is inter-operable among a class of hand-held devices, each of which is equipped with a mini-disk drive. A common digital data format is employed to further facilitate exchange of data between devices.

BACKGROUND OF THE INVENTION

This invention relates to an interchangeable cartridge data storagesystem and more particularly to a storage system in which amini-cartridge is compatible with devices generating signalsrepresenting different functions and the mini-cartridge is compatible,by use of a caddy, with a full size drive which can transfer signalsbetween that drive and a host computer.

Microprocessors and supporting computer technologies are rapidlyincreasing in speed and computing power while decreasing in cost andsize. These factors have led to the broad application of microprocessorsto an array of electronic products, such as hand-held computers, digitalcameras, cellular phones and the like. All of these devices have, ineffect, become computers with particular application-specificattributes. For this new breed of computer products, enormousflexibility is gained by the ability to exchange data files and storecomputer software.

A variety of proprietary storage devices have been used in computerproducts. For example, hand-held computers have used integrated circuitmemory cards ("memory cards") as the primary information storage media.Memory cards include memory storage elements, such as static randomaccess memory (SRAM), or programmable and erasable non-volatile memory,such as "flash" memory. Memory cards each are typically the size of aconventional credit card and are used in portable computers in place ofhard disk drives and floppy disk drives. Furthermore, memory cardsenhance the significant advantages of the size, weight, and batterylifetime attributes of the portable computer and increase portability ofthe storage media. However, because of the limited memory densityattainable in each memory card and the high cost of the specializedmemory chips, using memory cards in hand-held computers imposeslimitations not encountered in less portable computers, which typicallyuse more power-consuming and heavier hard and floppy disk drives astheir primary storage media.

Other of these computer products, such as the digital camera, haveemployed miniature video disks as the storage media. For example, U.S.Pat. No. 4,553,175 issued Nov. 12, 1985 to Baumeister discloses adigital camera configured to store information on a magnetic disk. InBaumeister, a signal processor receives signals representative of apicture from a photo sensor. Those signals are recorded on a magneticdisk for later processing. Unfortunately, the video disk storage productprovides limited storage capacity. For that and other reasons (e.g.,power consumption and cost), the video disk has not been used in othercomputer products. As a result, interchanging data from one of thesedigital cameras with other computer products, such as a hand-heldcomputer, is not readily achieved.

Miniature hard disk drives have also been suggested for use in portablecomputer products. For example, U.S. Pat. No. 5,469,314 issued Nov. 21,1995 to Morehouse et al. discloses a miniature hard drive for use inportable computer applications. In Morehouse, a hard disk drive isdescribed that is approximately 50 mm in diameter. While addressing manyof the problems presented by storage requirements in portable computers,the obvious problem of removability of the storage media is stillpresent.

Thus, Applicants have recognized that there is a long-felt need for astorage media that has adequate storage capacity and that addresses theneed for reduced size and interchangeability across a multitude ofcomputer products.

SUMMARY OF THE INVENTION

In accordance with the present invention a mini-cartridge is providedfor mini drives in a plurality of hand-held devices which generatesignals representing different functions performed by different classesof the devices. For example, the devices include digital cameras,electronic books, global positioning systems, personal digital systems,portable games and cellular phones. Each of these devices has a minidrive for writing signals and reading signals representing the functionsto and from a magnetic medium in the mini-cartridge. In this way,signals representing the diverse functions performed by the differentclasses of devices are recorded on the mini-cartridge. The hand-helddevices incorporating the present invention provide and create a singlemeans of capturing, moving and storing information across multipleproducts.

The mini-cartridge can be inserted into the mini drive of other devices.For example, a reporter could snap a photograph with a digital camerahaving a mini drive of the present invention, use a mini drive to saveand transport the image to a mini drive equipped cell phone and thentransmit the image to a news bureau, anywhere in the world.

The mini-cartridge from that cell phone can then be operated upon by apersonal computer. Further by way of example, the mini-cartridge can beinserted into a caddy which accommodates the mini-cartridge to make itcompatible with a full-size disk drive. The ZIP drive, marketed byIomega Corporation, is typical of a full-size drive which can read themini-cartridge because the caddy, in which the cartridge is inserted,makes it compatible with the full-size drive.

Full-size drives, such as the ZIP drive, are commonly included inpersonal computer systems. The full-size drive makes the signalsrecorded on a mini-cartridge readable. These signals are transmittedthrough the input/output channel and interface to a host computer whichoperates on the signals in the same manner as any other magneticallyrecorded signals.

As further example of the uses and advantages of the present invention,the mini-cartridge can be used in digital cameras similar to the wayfilm is used in a traditional camera, capturing up to 70-80 images on asingle disk at a low cost per disk. Currently, consumers must payhundreds of dollars for a flash memory card holding the same number ofimages.

The mini drive and cartridge can be used to quickly transfer a phonenumber list from a PDA to a cell phone, or save a fax on amini-cartridge and use it in a cell phone to transmit it wirelessly.

Hand-held gaming devices equipped with mini drives can also be an idealmeans of distributing games for hand-held gaming devices at lower costs.There is an additional possibility of updating games via the Internet,saving the new version on a mini-cartridge and then using it in ahand-held game player.

GPS (global positioning systems) using a mini drive can download mapsfrom the Internet, or a local map on a mini-cartridge can be purchasedfor use in a GPS system, while hiking or in a car equipped with a GPSdevice.

A PDA (personal digital assistant) with a mini drive is an affordablestorage technology for PC companions and hand-held devices. They alsoserve as a high-capacity, affordable means to save and move applicationsto/from a PC and PDA.

The present invention is designed to provide high capacity at a low costfor hand-held devices. The foregoing and other objects, features andadvantages of the invention will be better understood from the followingmore detailed description and appending claims.

SHORT DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe preferred embodiments, is better understood when read in conjunctionwith the appended drawings. For the purpose of illustrating theinvention, there is shown in the drawings embodiments that are presentlypreferred, it being understood, however, that the invention is notlimited to the specific methods and instrumentalities disclosed. In thedrawings:

FIG. 1 is a diagram of the interchangeable mini-cartridge of the presentinvention, including a plurality of devices each having a mini diskdrive, and including a caddy to adapt the mini-cartridge to a full-sizedrive of a host computer;

FIG. 2A shows a top view of the mini-cartridge with the shutterretracted exposing a magnetic medium;

FIG. 2B shows a bottom view of the mini-cartridge with the shutterretracted exposing the magnetic medium;

FIG. 2C shows a top view of the magnetic medium;

FIG. 3A shows the mini-cartridge seated in the mini disk drive with theread/write heads retracted;

FIG. 3B shows the mini disk de without the mini-cartridge;

FIG. 4A, FIG. 4B, FIG. 4C and FIG. 4D show the mini-cartridge atprogressive stages of insertion into the mini disk drive;

FIG. 4E shows the mini-cartridge fully translated horizontally into themini disk drive in an elevated, unseated position;

FIG. 4F shows the mini-cartridge seated in operational position in themini disk drive with the ads engaging the magnetic medium;

FIG. 5 shows the top of the mini disk drive exterior;

FIG. 6A shows the male camming surface and the cartridge lock fullyseated into the female camming surface and the cartridge lock matingsurface, respectively;

FIG. 6B shows the sled tab engagement with the eject tab;

FIG. 7A shows a top perspective view of the caddy without amini-cartridge;

FIG. 7B shows a top perspective view of the caddy with a mini-cartridgeinserted; and

FIG. 8 shows the interface between the full-size drive and the hostcomputer.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a plurality of devices 10-15 which generate signalsrepresenting different functions performed by different classes of thedevices. For example, the global positioning system 10 can generatesignals representing navigational position. Electronic book 11, digitalcamera 12, personal digital assistant (PDA/Palmtop) 13, portable game14, cellular phone 15, and laptop computer 16 each generate signalsrepresenting the function performed by that particular device.

In accordance with the present invention, each of these devices has amini drive 20 for writing the signals and reading the signals from amagnetic recording medium so that diverse functions performed bydifferent classes are recorded on the devices. Each device has a minidrive 20, i.e. a mini drive 20f for the global positioning system 10, amini drive 20g for the electronic book 11, a mini drive 20a for thedigital camera 12, a mini drive 20b for the portable game 13, a minidrive 20c for the PDA/palmtop 14, a mini drive 20d for the cellularphone 15 and a mini drive 20e for the laptop computer 16.

A mini-cartridge 30 has a magnetic recording medium on which the signalsfrom the devices are recorded. The mini-cartridge 30 is compatible withthe mini drives 20. Standard file formats maintain compatibility betweendevices. In the preferred embodiment, mini drives 20 have a PCMCIA type3 form factor. This form factor is commonly used in portable personalcomputers. For example, this form factor could be used for the modemport of a notebook computer. The PCMCIA type 3 form factor is quitesmall so the mini drive 20 readily fits into all of the portable,hand-held devices shown in FIG. 1. The mini-drive 20 is insertable intoand removable from the device just as the PCMCIA modem is insertableinto and removable from the PCMCIA slot of a notebook computer.Alternatively, the drive 20 could be hard wired into the device. In bothcases, the device generates a digital function signal which is connectedto the magnetic heads of the drive so that the digital function signalcan be written on the magnetic medium of the mini-cartridge 30. As anexample, a digital function signal representing a picture taken in adigital camera 12 is recorded on a mini-cartridge 30. This digitalfunction signal can be read by other classes of devices when thecartridge 30 is inserted into other devices.

Referring to FIGS. 2A and 2B a mini-cartridge 30 in accordance with thepresent invention is depicted. FIG. 2A presents an isometric top view ofmini-cartridge 30, and FIG. 2B presents an isometric bottom view ofmini-cartridge 30. Mini-cartridge 30 is fabricated from a magneticmedium 29 disposed between a top shell portion 41 and a bottom shellportion 34. Top shell portion 41 has four integrally formed pads 42, oneat each corner. Bottom shell portion 34 attaches to top shell portion 41within pads 42 and is formed from a substantially rigid materially, suchas sheet steel. Both the top shell portion 41 and the bottom shellportion 34 have cut-outs such that aperture 60 is formed in one end ofcartridge 30 when the shell halves are brought together.

Shutter 39 is connected over the aperture end of the mini-cartridge 30to close the aperture and protect the magnetic medium 29 whenevercartridge 30 is outside of a mini drive 20. As such, shutter 39 slidesto a first position indicated by line B, revealing magnetic media 29,and slides to a second position indicated by line A, closing theaperture and protecting magnetic media 29 from contamination and thelike. When shutter 39 is closed (i.e., moved to the position asindicated by line A), shutter latch 62 engages the slot 64 and locksshutter 39 in place. Thus, in order to move shutter 39 to the open (B)position, the latch 62 must first be depressed to unlock shutter 39.Four cam openings 59 are formed through the corresponding pads 42 of thetop shell portion 41 and two cartridge lock cut-outs 57 are also formedin the top shell. Additionally, the top shell portion 41 has a throughhole to allow a thinner mini-cartridge 30 while accommodating a drivespindle (not shown). As such, a seal 36, made of substantially thinnermaterial than the material used to form top shell portion 41, isattached to the shell to cover the hole. Magnetic medium 29, asindicated by the dashed line in FIGS. 2A and 2B, is sandwiched betweenthe shell portions 41, 34 and is allowed to float unattached to eithershell portion.

Magnetic medium 29 is best described with reference to FIG. 2C. Asshown, magnetic medium 29 is substantially circular in shape.Additionally, medium 29 is made from a single piece of flexiblematerial, such as Mylar. As is well-known in the floppy disk arts, amagnetic coating is placed over both sides of the Mylar, making itsusceptible to storing data in the form of magnetically readable anderasable signals. A circular hub 32 is attached to the medium 29 andprovides the mechanism for connecting the magnetic medium 29 to thedrive spindle. Hub 32 is stamped from a single piece of ferrousmaterial, such as sheet steel, forming circular lip 32a. Hub 32 andmagnetic medium 29 are permanently bonded together with a hot meltadhesive, such as bynel adhesive resin manufactured by DuPont Corp.

FIGS. 3A and 3B show a mini drive 20 with the top cover removed. FIG. 3Ashows the mini drive with a mini-cartridge 30 inserted and in anoperating position in the drive. FIG. 3B, by contrast, shows mini drive20 without a cartridge 30, revealing many of the internal drivecomponents. Toward the back portion of the drive, a voice coil actuator40 is coupled to drive platform 37. Actuator 40 has two arms 42a and 42bthat move linearly in the X axis direction in response to an electricalsignal. A read/write head (not shown) is coupled to the distal end ofeach arm 42a, 42b. Thus, when a mini-cartridge 30 is inserted into thedrive (as shown in FIG. 3A), the heads in conjunction with arms 42a, 42bmove over the surface of magnetic medium 29 reading and writing data.

The remaining internal components are best described with reference toFIG. 3B. As shown, spindle 49 is disposed toward the front of the driveplatform 37 and is centered about the width (i.e. the Y axis) of driveplatform 37. As with many disk drive spindles, spindle 49 provides therotational interface between the mini disk drive 20 and the magneticmedium 29. As such, spindle 49 has an alignment pin 49a that engages thecenter of hub 32, ensuring a consistent alignment of the medium 29 inthe mini disk drive 20. Additionally, spindle 49 has a magnetic topsurface 49b that magnetically couples hub 32 to spindle 49. To deriveits rotational force, spindle 49 is fixed to the drive motor rotor 50.Thus as the motor (only rotor portion shown) provides the rotationalforce to the motor rotor 50, spindle 49 also rotates, causing insertedmagnetic medium 29 to rotate.

Motor rotor 50 is magnetically coupled to the motor, which is a bushingtype pancake motor. That is, motor rotor 50 can be removed from themotor merely by overcoming the magnetic force that holds the motor rotorto its associated motor. Moreover, as stated above, mini-cartridge 30 ismagnetically coupled to spindle 49. As a result, removal ofmini-cartridge 30 from the drive 20 could cause motor rotor 50 to liftfrom the motor before the mini-cartridge 30 decouples from spindle 49.Motor hold-down wings 48, coupled to platform 37, prevent motor rotordecoupling. Accordingly, hold-down wings 48 overhang motor rotor 50.Clearance is provided between the overhanging hold-down wings 48 and themotor rotor 50 to allow motor rotor 50 to spin freely during normaloperation. When a mini cartridge 30 is ejected from drive 20, hold-downwings 48 will hold motor rotor 50 while hub 32 separates from spindle49.

A load/eject sled 45 is slidably disposed on drive platform 37 tofacilitate cartridge loading and ejection in cooperation with otherdrive components. Cams 58 are attached to or, alternatively, integrallyformed with, load/eject sled 45. The entire sled 45, in tandem with cams58, slides on drive platform 37 in a direction substantially parallel tothe X axis. Initially in a no-cartridge condition, sled 45 and cams 58are in the proximate position indicated by the line C. After amini-cartridge 30 is inserted, sled 45 and cams 58 move to a proximateposition indicated by line D. During cartridge 30 ejection, eject button46 is pushed by a user and, as a result of the force supplied by theuser, moves sled 45 from a position proximate to the line indicated by Dto a position proximate to the line indicated by C. Accordingly, cams 58are likewise forced to move to the position proximate to the lineindicated by C. As is described more fully below, this movement of cams58 causes a mini-cartridge 30 to eject from the drive 20. Additionally,as is described more fully below, cartridge locks 56 are fixed on bothsides of the drive platform 37 and are used to engage and lock amini-cartridge 30 to drive platform 37 during the cartridge insertionprocess. These cartridge locks 56 cooperate with cams 58 to providecartridge 30 insertion and ejection.

A head protect lever 52 is pivotally mounted at its proximate end todrive platform 37 and secures the read/write heads when no cartridge isin the drive 20. Pivot pin 54 is connected to the proximate end of headprotect lever 52 and rides in head release slot 51 of load/eject sled45. When no cartridge 30 is in the drive, head release slot 51 allows aspring to actuate head protect lever 52 rearwardly via pivot pin 54. Asa result, arms 42 are retracted. On the other hand, when a cartridge 30is inserted into drive 20, head release slot 51 forces head protectlever 52 forward, releasing arms 42 and enabling them to move overmedium 29.

A cartridge eject lever 47 is pivotally mounted proximately in the backof the drive platform 37 in front of actuator 40. As is described morefully below, lever 47 provides two functions: Opening shutter 39 duringcartridge 30 insertion; and ejecting cartridge 30 during cartridgeejection.

The insertion of a mini-cartridge 30 into mini drive 20 is bestdescribed with reference to FIGS. 4A through 4F and 5. Starting withFIG. 4A, a mini-cartridge 30 is outside of drive 20 (with the cover andfront panel removed for clarity) prior to insertion. At that moment,cams 58 are proximate to the position indicated by line C. Head protectlever 52 has arms 42 in a retracted position. Eject lever 47 is biasedin a counter-clockwise position. And, sled 45 is locked into theposition proximate to line C, via eject lever tab 47 engaging sled tab53, and spring loaded by sled spring 66 (best viewed in FIG. 3B).

Referring now to FIG. 4B, as mini-cartridge 30 enters drive 20, it ridesalong the top of the forward set of male cams 58c, 58d. Front female camopenings 59a, 59b in mini-cartridge 30 are sized and located such thatthey do not match-up with the first set of male cams 58c, 58dencountered by the mini-cartridge 30. As a result, male cams 58c, 58dlift cartridge 30, ensuring that it enters above and clears spindle 49during mini-cartridge 30 insertion into drive 20.

Referring next to FIG. 4C, as mini-cartridge 30 enters further intodrive 20, nose 47a of eject lever 47 enters shutter slot 64 and contactsthe mini-cartridge shutter latch 62. As mini-cartridge 30 is urged yetfurther into drive 20, eject lever 47 pivots clockwise and moves shutter39 away from media aperture 60, exposing the magnetic medium 29 disposedwithin the mini-cartridge shell. Meanwhile, spring 43 provides acounter-clockwise bias on eject lever 47. Thus, simultaneous to ejectlever 47 opening shutter 39, eject lever 47 is spring loaded.Additionally, as eject lever is rotated clockwise, eject lever tab 47a,which is integrally formed with eject lever 47, also begins to rotateclockwise.

FIG. 4D shows mini-cartridge 30 in the most forward position in drive20. At that moment, shutter 39 is fully open and eject lever 47 ispivoted fully clockwise and loaded against spring 43. However, cartridge30 is not yet seated on spindle 49 and head protect lever 52 has not yetreleased the heads. Eject lever tab 47a is now fully rotated clockwise,away from sled tab 53 (see FIG. 6B for best view of eject lever tab 47aand sled tab 53 engagement).

FIG. 4E shows the release of sled 45 and forward movement of sled 45.After the eject lever tab 47a has moved away from sled tab 53. The sledis free to move from a position proximate to line C to a positionproximate to line D. With the sled now free, spring 66 provides the biasto move sled 45 accordingly. As a result of the sled movement, cams 58are moved to the D position, providing proper alignment withcorresponding cam openings 59 and head protect slot 51 moves forwardengaging pin 54 and releasing head protect lever 52.

FIG. 5 in conjunction with FIG. 4F, illustrates the final mini-cartridge30 loading step. Referring first to FIG. 5, cantilever springs 55 areshown extending downwardly from drive cover 22. These cantilever springs55, force mini-cartridge 30 down as cartridge 30 fully enters drive 20.However, cartridge 30 is forced by cams 58 to a raised position untilcam openings 59 on the mini-cartridge 30 are properly aligned with thematching male cams 58 on the sled 45. At that moment, the cantileversprings 55 urge mini-cartridge 30 downwardly onto male cams 58, as shownin FIG. 4F. Substantially simultaneous to the cam engagement, drivespindle 49 enters the corresponding circular lip 32a on themini-cartridge 30 and magnetically engages hub 32.

According to an aspect of the invention, wedge locks 56 engage thecorresponding wedge cut-outs 57 on the mini-cartridge shell. FIG. 6Aprovides an expanded view of the interlocking of wedge 56b with cut-out57b in cartridge 30. Wedges 56 provide a ramped surface on their frontside and an acute angled surface on their back sides. The angledsurface, as indicated by the angle α, is about 80° in the presentembodiment. However, those skilled in the art will recognize that otherangles could be substituted for 80 degrees while still providingsatisfactory results. Eject lever 47 (shown in FIG. 4F) applies atranslational bias to cartridge 30, urging cartridge 30 outwardly. As aresult, wedges 56 in cooperation with eject lever 47 lock cartridge 30into place in drive 20. Mini-cartridge 30 is now ready for access by theread/write heads.

When a user desires to eject a cartridge 30 from the drive, the processis substantially reversed. The user begins by pushing the eject button46. The force of this action causes cams 58 to move from their locationproximate to the line indicated by D toward a point proximate to theline indicated by C. As best understood in conjunction with FIG. 6A,such lateral translation causes cams 58 to engage the correspondingfemale cammed surfaces 59. As cams 58 move further toward a positionproximate to the D line, cartridge 30 begins to lift vertically fromdrive 20 (in the Z axis direction). When cams 58 are moved substantiallyto the D line, the bottom of cartridge 30 lifts above the top of spindle49 and the top of wedges 56. Simultaneously, sled tab 53 is also movedtoward the rear of the drive once sled 45 has moved to a position Atthat moment, spring 43 pivots the eject lever 47 counterclockwise,simultaneously ejecting the cartridge 30 and closing shutter 39.

In order to provide forward compatibility to the host computer 23, acaddy 31 is provided. Caddy 31 adapts the mini-cartridge 23 to a fullsize drive 33. The full size drive 25 is the aforementioned ZIP drivewhich is disclosed and claimed in U.S. Pat. No. 5,530,607, entitled"WING ATTACHMENT FOR HEAD LOAD/UNLOAD IN A DATA STORAGE DEVICE" by JaySpendlove on Jun. 25, 1996 and U.S. Pat. No. 5,508,864 entitled"FLEXURES WHICH REDUCE FRICTION IN AN ACTUATOR FOR DATA STORAGE DEVICE"by John Briggs granted on Apr. 16, 1996 and in U.S. Applications Ser.No. 08/398,576 filed Mar. 3, 1995 entitled "HEAD PARK MECHANISM IN ADATA STORAGE DEVICE FOR PREVENTING ACCIDENTAL DAMAGE" by David Jones andU.S. patent application Ser. No. 08/398,576 filed Mar. 3, 1995 entitled"Movable Internal Platform for a Disk Drive." These applications areincorporated herein by reference.

Obviously, a mini-cartridge 30 and a full-size cartridge have a numberof differences that prevent the mini-cartridge from directly operatingin a full-size drive. Perhaps, the most obvious of these differences issize. Mini-cartridge 30 has a much smaller form factor than a full-sizedrive cartridge. Whereas, a mini-cartridge is about 17/8" square andabout 1/10" high, a full size drive cartridge is about 37/8" square and1/4" high. Other differences between the cartridges and the drives alsorequire adaptation to enable a mini-cartridge 30 to operate in afull-size drive. For example, the mini-cartridge rotates slightly fasterthan the rotation rate of a full size drive cartridge (e.g., 3267 rpmsversus 2960 rpms for a full-size drive cartridge). Caddy 31, describedmore fully below, accepts a mini-cartridge 30 and adapts it for use in afull-size drive.

Referring to FIGS. 7A and 7B, a presently preferred embodiment of caddy31 is presented. FIG. 7A shows caddy 31 without a mini-cartridge 30,revealing the internal components of caddy 31. FIG. 7B shows caddy 31with a mini-cartridge 30 snapped into place. As is best shown in FIG.7A, caddy 31 comprises a caddy body 70 for carrying and adapting themini-cartridge form factor to the full-size form factor, a drivemechanism 72, 74, 76 for translating power from the full-size drive axisof rotation to the mini-cartridge axis of rotation, a spindle 78 forrotating mini-cartridge 30, and a gear cover 86 for securing main gear72.

Caddy body 70 is shaped and sized to substantially the same dimensionsas a full-size ZIP cartridge and has special features added to adapt amini-cartridge 30. A depression 81 is formed in the top of caddy body70. Depression 81 has a rectangular footprint for accepting a minicartridge 30, and has an adjacent rectangular depression 84 to providespace for the insertion of main gear 72. A cover 86 is disposed overtopdepression 84 for holding main gear 72 in place, while allowing gear 72to adjust to the full-size drive spindle. The depth of depression 81 issuch that magnetic medium 29 is disposed at about half the height ofcaddy body 70, thereby aligning the medium 29 with the heightrequirements of the full-size medium. Caddy body 70 also includes alower depression 85. Depression 85 provides space for the drivemechanism 72, 74, 76 to reside below the space occupied bymini-cartridge 30 and provides an opening for the lower full-size driveread/write head to enter the caddy 31 and access magnetic medium 29.

The drive mechanism 72, 74, 76 translates power from the full-size drivemotor and spindle to spindle 78 for rotating a mini-cartridge 30 placedin caddy 31. Main gear 72 emulates a full-size cartridge hub and couplesto the full-size drive spindle. As such, main gear 72 floats, as does afull-size cartridge hub, and adjusts its location to engage thefull-size drive spindle. Thus, when caddy 31 is inserted into afull-size drive, the full-size drive spindle engages main gear 72 as ifgear 72 were a full-size drive hub and the caddy were a full-sizecartridge. As such, main gear 72 is formed of a ferrous material, oremploys a ferrous material, to allow magnetic coupling with thefull-size drive spindle. As the full-size spindle rotates main gear 72,power is provided to the entire drive mechanism of caddy 31.

Gears 74 and 76 translate power from main gear 72 to spindle 78. Gears74 and 76 are rotatably coupled to caddy body 70 by conventionalmethods, such as metal or plastic pins. Spindle 78 is fixed to spindlegear 76 such that when gear 76 rotates, spindle 78 also rotates.Furthermore, the center axes of spindle 78 and spindle gear 76 arecoincident, ensuring that a stable axis of rotation is provided to amini-cartridge 30 inserted into caddy 31. Spindle 78 is located withinthe caddy body 70 such that it engages magnetic medium 29 (see FIG. 7B)at the appropriate height and plane (i.e., on the same plane as mediafor a full-size drive). Furthermore, spindle 78 emulates the spindle ofa mini-drive 20 in engaging a mini-cartridge 30. That is, spindle 78magnetically couples with hub 32 of a mini-cartridge 30 inserted intocaddy 31.

During operation, main gear 72 rotates clockwise in accordance with therotation of the full-size drive motor. Obviously, spindle 78 must alsorotate clockwise so that medium 29 rotates properly in the full-sizedrive. Accordingly, intermediate gear 74, is coupled between gear 72 andgear 76. As gear 72 rotates clockwise, gear 74 rotatescounter-clockwise, causing gear 76 and spindle 78 to also rotateclockwise. Furthermore, as noted above, medium 29 of mini-cartridge 30rotates within a mini drive 20 at the same angular rotation as afull-size cartridge medium rotates within a full-size drive. Because ofthe obvious size differences, the angular rotation of a mini-cartridgemedium 29 translates to a rotational speed that is slightly faster thanthe rotational speed of a full-size medium. When operating in caddy 31,the same proper rotation speed of a mini-cartridge 30 must bemaintained. Accordingly, gear ratios of 72, 74, 76 must be selected suchthat the magnetic medium 29 rotates at an angular velocity approximatelyequal to the angular velocity of full-size drive magnetic medium, orabout twice the rotational speed.

Additionally, a point on the circumference of the medium 29 farthestfrom the centroid of the main drive mechanism 72 defines a forward-mostpoint 82. The forward-most point 82 also lies on a center axis 80, whichis defined by points where the vertical center axes of the main drivemechanism 72 and of the spindle 78 bisect the plane defined by themedium 29. The spindle 78 is located along the center axis 80 such thatthe forward-most point 82 of the mini cartridge medium 29 is coincidentwith a forward most point of a full-size medium of a standard, full-sizedisk cartridge. Such location of the mini cartridge medium 29 enablesthe heads of the full-size drive to properly engage the medium 29.

Those skilled in the art will readily appreciate that many modificationsto the caddy are possible within the scope of the invention. Forexample, a belt drive mechanism could be used in place of gears, oradditional gears could be used to provide a more stable rotation.Accordingly, the caddy is not limited to the single embodimentdisclosed.

The ZIP drive 33 has an interface 24 for transferring signals betweenthe full size drive 33 and the host computer 35. The interface 34 isshown in FIG. 8.

FIG. 8 shows the ZIP drive interface 26 between the read write channelfor the disk (lower right side of diagram) and the host computer (upperleft side of diagram). It includes an AIC chip 101 which performs theSCSI 102, the DMA 103, and disk formatter 104 functions. The interfacealso includes a PHAEDRUS 105 which includes an 8032 micro controller106, a 1K Ram 107 and an ASIC 108. The ZIP interface transfers databetween the input/output channel of the ZIP drive and SCSI devices suchas the host computer.

Although a particular embodiment of the invention has been shown anddescribed, other embodiments and modifications will occur to those ofordinary skill in the art which fall within the scope of the appendedclaims.

What is claimed is:
 1. An interchangeable cartridge data storage systemcomprising:a plurality of devices for generating signals representingdifferent functions performed by different classes of said devices: amini-cartridge having a medium on which said signals are recorded; and amini drive in said devices for writing said signals and reading saidsignals from said medium so that diverse functions performed by saiddifferent classes of said devices can be interchangeably operated uponby said devices.
 2. The data storage system recited in claim 1 furthercomprising;a full size drive larger than said mini drive andaccommodating a cartridge which is larger than said mini-cartridge; andmeans for adapting said mini-cartridge to said full size drive to makesaid devices forward compatible with said full size drive.
 3. The datastorage system recited in claim 2 further comprising:a host computer,said full size drive having an interface for transferring signalsbetween said full size drive and said host computer.
 4. The data storagesystem recited in claim 2 where said full size drive accommodates a fullsize cartridge and wherein said full size cartridge has a recordingmedium on which said signals are recorded and from which said signalscan reproduced.
 5. The data storage system recited in claim 4 whereinsaid medium in said mini-cartridge and said medium in said full sizecartridge are a flexible magnetic disks.
 6. The data storage systemrecited in claim 2 further comprising;a caddy for accommodating saidmini-cartridge to make it compatible with said full size disk drive. 7.The data storage system recited in claim 6, wherein said full size drivehas a spindle motor and wherein said caddy has means for translating thecenter of rotations of said spindle motor to a different center ofrotation of said mini-cartridge.
 8. The data storage system recited inclaim 7 wherein said caddy has means for changing rotational speed froma lower rotation speed of said full size cartridge to a higherrotational speed of said mini-cartridge.
 9. The data storage systemrecited in claim 1 wherein said different classes of devices includedigital cameras, electronic books, global positioning systems, personaldigital systems, portable games, cellular phones and digital cameras.